1. Field of the Invention
This invention relates to a variable optical-property optical element such as a variable focal-length lens, a variable focal-length diffraction optical element, a variable deflection-angle prism, or a deformable mirror, and to an optical apparatus such as spectacles, a video projector, a digital camera, a TV camera, an endoscope, a telescope, or a camera finder, having an optical system including such a variable optical-property optical element.
2. Description of Related Art
Conventional lenses have been manufactured by polishing glass. Since the lens it-self cannot vary a focal length, a mechanical structure is complicated because a lens unit must be moved along the optical axis for focusing or zooming of a camera, or changing magnification.
Because a motor or the like is used for moving a part of the lens unit, this conventional practice has disadvantages that power consumption is large, noise is produced, response time is long, and much time is required for moving lenses.
For shake prevention as well, mechanical movement of the lenses by a motor or a solenoid causes defects such as a large power consumption and a complicate mechanical structure, resulting in a higher cost.
It is, therefore, an object of the present invention to provide a variable optical-property optical element such as a variable focal-length lens, a deformable mirror, or a variable deflection-angle prism, which is low in power consumption, quiet, short in response time, and simple in mechanical structure and contributes to cost reduction, and an optical system and an imaging device or an optical apparatus, including such variable optical-property optical elements.
In order to achieve this object, the optical system, for example, according to the present invention is provided with a deformable mirror, which bends the optical axis to form an image of an object on an imaging plane. In this case, the optical system has a two-dimensional look-up table (LUT), with a zoom state and a distance to an object as input information, storing the value of a voltage applied or a current supplied to the deformable mirror, as output information, which corresponds to the zoom state and the distance to the object. The two-dimensional LUT is scanned in turn in image formation and the value of the voltage applied or the current supplied to the deformable mirror is changed in accordance with acquired output information to determine the sharpness of a formed image so that the output information of the two-dimensional LUT where the sharpness of the formed imaged is optimized is decided as the value of the voltage applied or the current supplied to the deformable mirror.
The optical system, for example, according to the present invention is such that when one of the zoom state and the distance to the object is detectable in image formation, the zoom state or the distance to the object, having been detected, is fixed. The two-dimensional LUT is scanned in turn in image formation and the value of the voltage applied or the current supplied to the deformable mirror is changed in accordance with acquired output information to determine the sharpness of a formed image so that the output information of the two-dimensional LUT where the sharpness of the formed imaged is optimized is decided as the value of the voltage applied or the current supplied to the deformable mirror.
The optical system, for example, according to the present invention is provided with a deformable mirror, which bends the optical axis to form an image of an object on an imaging plane. In this case, the optical system has a two-dimensional look-up table (LUT), with a zoom state and a distance to an object as input information, storing the value of a voltage applied or a current supplied to the deformable mirror, as output information, which corresponds to the zoom state and the distance to the object. When one of the zoom state and the distance to the object is detectable in image formation, the zoom state and the distance to the object are fixed to input the two-dimensional LUT so that acquired output information is decided as the value of the voltage applied or the current supplied to the deformable mirror.
The imaging device, for example, according to the present invention is mounted with a zoom lens. In this case the imaging device has a variable mirror.
Further, the imaging device, for example, according to the present invention has at least two variable mirrors.
Still further, the imaging device, for example, according to the present invention uses the variable mirror as a focusing means.
This and other objects as well as the features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments when taken in conjunction with the accompanying drawings.